Beam torque wrench

ABSTRACT

A novel connecting means between the ends of an elongate deflection and work-engaging head and hand gripping parts related thereto, said means comprising socket openings in said parts in axial alignment with the beam and having substantially flat bottoms opposing substantially flat ends on the beam, radially inwardly opening lock grooves in the socket openings adjacent the bottoms thereof and lock beads forged on the beam adjacent the ends thereof and projecting radially into the lock grooves. The inner faces of the beam ends and socket bottoms and the inner faces of the lock beads and lock grooves being welded.

United States Patent 91 Vuceta Apr. 10, 1973 [73] Assignee: Consolidated Devices, Inc., San

Gabriel, Calif.

22 Filed: Apr. 12,1971

21 Appl.No.: 133,015

[56] References Cited UNITED STATES PATENTS 2/1941 Zimmerman ..73/ 139 8/1948 Odlum ..29/483 X 3,444,61 l 5/1969 Bogart ..29/470.3

Primary Examiner-Charles A. Ruehl Attorney-Georges A. Maxwell ABSTRACT A novel connecting means between the ends of an elongate deflection and work-engaging head and hand gripping parts related thereto, said means comprising socket openings in said parts in axial alignment with the beam and having substantially flat bottoms opposing substantially flat ends on the beam, radially inwardly opening lock grooves in the socket openings adjacent the bottoms thereof and lock beads forged on the beam adjacent the ends thereof and projecting radially into the lock grooves. The inner faces of the beam ends and socket bottoms and the inner faces of the lock beads and lock grooves being welded.

6 Claim, 8 Drawing Figures BEAM TORQUE WRENCH This invention has to do with an improved torque wrench construction.

The most common and widely used form of torque indication wrench consists of an elongate deflection beam or lever arm with a handle at one end, a work-engaging head at its other end, a calibrated dial carried by the handle or carried by the beam adjacent the handle and an elongate rigid, rod-like pointer carried by the work-engaging head normally extending substantially parallel with the beam and having a free end adjacent and directed to the calibration on the dial face. As force is applied onto the handle, through the beam and head and thence to a piece of work engaged by the head, the beam yieldingly bends or is deflected an extent proportional to the applied force, which deflection is predetermined and is utilized in calibrating the dial face. Upon such deflection of the beam, the pointer swings across the dial face or along theline of calibrations thereon to point toward the calibration or calibrations which corresponds to the applied force and in such a manner that the operator of the wrench can read the related dial face and pointer and thereby determine the magnitude of the applied force.

In constructing such wrenches, the beams must be carefully and accurately established and extreme care must be taken during manufacture of the wrenches not to upset the physical characteristics of the beams.

In order that such wrenches can be mass produced at reasonable costs, it has been determined that the deflection beams must be established of carefully and accurately produced, uniform stock and that as little work be performed on the beams as is possible. To this end, for example, the deflection beams of wrenches of the class here concerned with are established of round, centerless ground 4130 steel, heat treated to 48 Rockwell C. Such beam stock is obtainable by the wrench manufacturer from a suitable mill source, in predetermined. and desired diameter and length. 80 long as no major work is required to be performed on the beams thus acquired, the cost of producing wrenches of the character referred to is kept at a minimum and within a practical range.

To the above end, it has been the common practice of the prior art in manufacturing wrenches of the character referred to to obtain deflection beams in the manner set forth above, establish handles with tubular bores therein and in which one end of the beamsare slidably engaged and held by set screws or the like and to establish work-engaging heads with bores therethrough in which the other ends of the beams are slidably engaged and held by set screws or the like. The dial faces and pointer are, as indicated above, separate parts suitably fixed to and carried by their related han-' dles or beams and their related heads. With such a method of assembly, the beams are undisturbed.

The principle shortcoming found in such constructions resides in the fact that the fit between the workengaging heads and the beams is not fixed and immovable, with the result that the heads move or rock slightly relative to the beams when forces are applied.

During repeated cycling of the wrenches, the noted relative movement and working progressively increases. Due to the nature of such wrenches and the manner in which the pointers, carried by the heads, are

related to the dial faces (a substantial distance from the heads) any movement of the heads relative to the beams is multiplied and manified many times at the free ends of the pointers and on the dial faces, and the wrenches are rendered inaccurate and incapable of accurately indicating applied forces.

In practice, where the beam receiving bores in the heads are accurately established so that no appreciable movement occurs between the heads and beams the inherent resiliency of the metal from which the heads are established will frequently permit slight initial movement between the parts under applied forces, which initial movement of parts initiates the progressive increase of play, as indicated above.

The necessity to minimize play or movement between the beams and heads in such wrenches requires that the beam receiving bores in the heads be as long or deep as is possible and that they be established as carefully'and as accurately as manufacturing techniques permit. As a result of the above, the establishment of such bores is a time consuming and very costly step or operation in the manufacture of such wrenches.

In efforts to overcome the above shortcoming found in wrenches of the character referred to, efforts have been made to heli-arc weld the heads to the beams. Such attempts have failed to achieve satisfactory results as such welding can not be performed with sufficientuniformity and results in burning the metal parts to an extent that the physical characteristics of the beamsare upset and with the end result that a uniform product can not be produced.

In certain of my efforts to overcome the above shortcoming, flat ends of deflection beams were inertia welded to or with related flat surfaces established on the heads, without adverse effects to the physical characteristics of the beams. Inertia welding, which is a form of friction welding, does not utilize or require the application of destructive or damaging heat, but does result in the creation of a substantial, undesirable and unsightly bead-like flashing about the perimeter of the weld, which flashing must be removed. The noted flashing is created by plastic metal, displaced during the welding operation. Due to exposure of the weld flashing to atmosphere and rapid quench thereof, it is extremely hard. Removal of the noted flashing therefore requires that the welded together parts be annealed; that the flashing then be machined away and that the assembly be heat treated again. These additional steps, required to establish an attractive, finished looking and marketable product, are time consuming and costly and are therefore undesirable.

An object of my invention is to provide an improved wrench construction of the character referred to and a novel method of making the same.

It is another object of this invention to provide a 'novel and improved connecting structure between the heads and the beams and/or between the beams'and the handles of wrenches of the character referred to whereby the connected parts are permanently and immovably fixed together.

Yet another object and feature of my invention is to provide a novel connecting means which is such that the connected parts are mechanically and possitively interlocked one within the other and wherein the interlocking parts or portions are integrally joined and welded together.

Another object and feature of this invention is to provide a novel connection for fixedly joining two related parts where a socket opening with a radially inwardly opening groove adjacent its bottom end enters and extends into the interior of one part and the other part projects into the socket to the bottom thereof and has an annular radially outwardly projecting bead forged integrally thereon and projecting into and completely occupying the groove.

Still another object and feature of my invention is to provide a connection as set forth above wherein the mating, opposing, inner faces of the parts are welded together.

It is an object and feature ,of this invention to provide a connection of the character referred to wherein the socket need only be sufficiently deep to afford establishment of a suitable annular locking groove within the exterior part in which it is formed and a connection wherein the inner part is forged within the outer part whereby the tolerances to which the-preconnected parts must be established for purposes of connecting them are wide and non-critical.

It is an object of this invention to eliminate the requirement to carefully and accurately drill long or deep bores in an outside part to receive and provide supporting engagement for an inner part engaged therein and to establish and utilize secondary means to secure the interengaged parts together.

Yet another object of this invention is to provide a connection of parts such as referred to above wherein the mass quenched and hardened welded material is within the outer part and establishes a hard, tough and strong core therein and within the connection.

The foregoing and other objects and features will become apparent and will be fully understood from the following detailed description of a typical preferred form and application of the invention, throughout which description reference is made to the accompanying drawings, in which:

FIG. 1 is an isometric view of a wrench embodying the present invention;

FIG. 2 is a view showing beam and head connecting means employed by the prior art;

FIG. 3 is a view showing beam and handle connecting means employed by the prior art;

FIG. 4 is a sectional view taken substantially as indicated by line 4-4 on FIG. 1;

FIG. 5 is a sectional view taken substantially as indicated by line 5-5 on FIG. 4;

FIG. 6 is a sectional view taken substantially as indicated by line 66 on FIG. 4;

FIG. 7 is a view showing parts related preparatory to connecting them; and,

FIG. 8 is a view'showing the connection between the beam and the handle.

For the purpose of illustration, I have, in FIG. 1 of the drawings, shown a typical deflection beam type of torque wrench, which wrench includes an elongate cylindrical deflection beam B, a work-engaging head H at one end of the beam, a handle or hand grip G at the other end of the beam, a plate-like dial face D carried by the grip G or by the beam B adjacent the grip, and an elongate pointer P carried by the head and extending to the dial face.

The beam B is an elongate unitary part and will, for the purpose of description, be described as extending horizontally. The beam is of uniform round cross-section, has flat front and rear ends 10 and 11 and is of uniform hardness and resiliency. For example, the beam is centerless ground 4130 steel and is heat treated to 48 Rockwell C. The beam is of predetermined longitudinal and diametric extent and is such that it is most conveniently and advantageously purchased as a finished product from a steel mill.

The head H is a unitary machined part having an elongate vertically extending cylindrical body portion 12 with upper and lower ends 13 and 14, a horizontal rearwardly opening beam receiving opening 15 intermediate its ends and a horizontal rearwardly opening pointer receiving opening 16 above the opening 15. The head H further includes an elongate vertically extending polygonal work-engaging stem 17 such as is commonly provided on wrench lever arms to engage wrench sockets and the like. The stem 17 depends from the lower end 14 of the body and is concentric therewith.

The machined wrench head I-I, described above, is preferably metalurgically similar to the beam and in the example given is established of 4130 steel, heat treated to 48 Rockwell C.

In accordance with common practice, the stem 17 is provided with a spring loaded retaining ball 18 in one of its sides or faces to facilitate releasably holding a socket or the like engaged thereon.

g In FIG. 2 of the drawings, I have illustrated a typical or common connection between a wrench head H and beam B and as is produced and provided by the prior art. In this common connecting means, an opening 15' in the head II extends through the body portion 12' of the head and is adapted to slidably receive the forward portion of the beam B. The opening is extended through the head, as shown so as to provide maximum aligning support and engagement of the head and the beam and to utilize maximum possible or allowably supporting stock in the head. a

To maintain the head II and beam B engaged, a set screw opening 20 is commonly drilled and tapped in one side of the head to intersect the opening 15' and a set screw 21 is entered and advanced in the opening 20 to engage the beam B.

The necessity to drill the opening 15' clear through the head H or sufficiently deep therein to provide beam aligning engagement between the head and the beam is costly and time consuming. Further, the requirement to provide retaining means, such as the set screw means described above, to maintain the head and beam assembled is time consuming and costly.

In practice, the common head and beam connection shown in FIG. 2 of the drawings is subject to initial play and movement. Such play and movement is caused by original clearances between the opening and the beam and/or clearances therebetween which develop during the normal use and cycling of the structure.

In FIG. 2 of the drawings, the dotted lines W indicate the direction and the manner in which clearance and play between the head H and the beam B is developed and manifested.

It has been determined that even when the initial,

tainable with practical manufacturing methods and procedures) the inherent resiliency of the parts, when in use and stressed, permits slight working between the parts which working frequently, progressively increases as the structure is used.

When the head H and beam B work relative to each other in the manner indicated above, the axis of the beam B shifts relative to the head, as indicated by the phantom outer lines X in FIG. 2 of the drawings and with the result that the axis of the beam B and the pointer P, which pointer is in fixed relationship to the head, are subject to relative angular displacement, rendering the pointer and dial face of the wrench out of proper register and the wrench inaccurate and undependable.

In the instant invention and as illustrated in FIGS. 4 through 7 of the drawings, the opening in the head H is of limited depth and terminates in the body 12 at a flat rearwardly disposed bottom The diameter of the opening 15 is preferably such that it establishes a snug and/or sliding fit with the beam B, but can be substantially larger than the beam, so as to freely receive the beam, without adverse effects.

The opening 15 that I provide is and will be referred to as a socket or socket opening and is characterized by an annular, radially inwardly opening lock groove 26 in its bore, adjacent the bottom 25.

The groove 26 is preferably round or semi-circular in cross-section and is related to the bottom 25 so that its inner edge fares into and with the bottom 25, as clearly shown in the drawings.

In practice, the groove 26 could be polygonal or made up of radiused and flat surfaces and planes without departing from the spirit of or adversely effecting the novelty of my invention.

The surfaces of the socket opening 15, including its noted groove 26, need not be smooth finished surfaces, but can be roughly cut surfaces without adverse effects.

The forward end portion of the beam B is entered into and engaged in the socket opening 15 in the head with its flat front end 10 at the bottom 25 of the socket opening and is provided with a radially outwardly projecting annular flange-like retaining bead 30 which extends into and completely occupies the groove 26, establishing a mechanically interlocked connection between the beam and the head which fixes the beam in the head against longitudinal axial shifting and/or radial swinging or shifting of the beam relative to the head.

The opposing surfaces or inner faces of the bead 30 and groove 26, and of the inner end 10 and bottom 25 are welded and integrally joined together, establishing an integrated structure which is incapable of play or movement between the parts or portions thereof.

The establishment of the bead 30 on the beam and within the groove 26 and the welding of the parts together as above set forth is accomplished or effected by holding one of the parts fixed, for example, holding the head fixed, by rotating the other part, or beam (without the bead 30 yet form'ed thereon) and advancing the beam into the grooved socket until its front end 10 establishes pressure friction engagement with the bottom 25 of the socket. Then continuing to rotate the beam and apply sufficient axial pressure between the bottom 25 and end 10 to generate, by friction, sufficient heat to render the metal adjacent the engaged surfaces plastic and, at the same time, advancing the beam axially into the socket opening a sufficient distance to displace and forge the plastic metal radially outwardly into the groove, to completely occupy said groove and forge the locking bead on the beam.

In carrying out the above process or method of assembling, the beam and head, the metal of the head and of the beam adjacent the inner faces at the bottom of the socket opening and front end of the beam are rendered sufficiently plastic and fluid to establish a deep weld between the parts.

The temperature of the mass of metal in the head adjacent the bottom of the socket opening and about the groove 26, the temperature of the metal adjacent the front end 10 of the beam and the temperature of the metal establishing the bead 25, as the bead is forged on the beam and into the groove, is sufficient and such that the inner faces of the bead and groove weld together and the head is welded with and is an integral part or portion of the beam.

In practice, it is not necessary that the inner faces of the bead and groove weld together. It is sufficient that the inner faces of the bottom of the socket opening and front end of the beam weld together and the bead substantially occupies the groove, to establish positive mechanical locking engagement between the parts.

When the parts are connected in the above manner, the plastic metal is moved radially and circumferentially outwardly between and relative to the bottom 25 of the beam, as indicated of the arrows Y in FIG. 5 of the drawings, and is moved outwardly and rearwardly in the groove 26 in the direction indicated by the arrows Z in FIG. 7 of the drawings. Such movement is effected under considerable pressure and results in a weld having a fine, dense, spiral grain pattern and a weld which is notably stronger than the raw metal employed in its establishment.

The heated, forged and welded metal in the connection here provided is mass quenched, that is, it is quenched by the heat sink effect or heat conduction of the adjacent and surrounding mass of the metal establishing the joined or connected parts. The heating of the parts is of sufficient extent and magnitude and the mass quenching of the heated material is such that the bead, the weld or welds and the heated masses thereabout are quenched to a hardness of about 50 to 52 Rockwell C, defining a harder and tougher core within the body of the head. An example of the extent of the hardened core is shown in dotted lines in FIGS. 4, 5, and 6 of the drawings.

It is notable that in regular friction or inertia welding of parts, the flashing of plastic metal characteristically established about the parts is exposed and air quenched. In such welds, and where metals of the above given example are employed, the noted flashings are about 60 Rockwell C or greater, are not under pressure when formed, are coarse grained and undesirably brittle.

In light of the above, it will be noted and appreciated that with and in carrying out the instant invention, quenching and hardening of the heated and welded materials is advantageously controlled.

In FIG. 3 of the drawings, I have illustrated a typical manner in which the prior art connects the rear end of the beams B of wrenches of the class here concerned with with the hand grips G of such wrenches.

The connection now under consideration is essentially the same as the connection between the beam B and head H, shown in FIG. 2 of the drawings. The rear end portion of the beam B is slidably engaged in an opening 15 entering the front end of the hand grip G and is held fixed therein by a set screw 21.

The opening i5 must be sufficiently deep and the end portion of the beam engaged thereon must be sufficiently long to impart desired alignment of the grip and beam.

With the structure shown in FIG. 3, it will be noted that the grip and beam are subject to working and developing play relative to each other and that such working and play will result in misalignment of the grip and beam in the manner indicated by the phantom center lines X.

If the dial face is fixed to and carried by the grip G, the above working and misalignment of the grip and beam renders the wrench inaccurateand undependable.

Since the construction of the dial D and the manner in which the dial is mounted or fixed in place does not effect this invention and since it can, in practice, be fixed to the beam or to the hand grip, I have elected not to burden this disclosure with illustration and detailed description of the dial and its mounting means.

In accordance with the present invention and as shown in FIG. 8 of the drawings, the rear end 11 of the beam and the hand grip G are connected and fixed together in the same manner that the head H and beam are fixed together. The hand grip G has a socket opening 15" with a flat bottom and lock head forged thereon and occupying the groove 26.

In FIG. 8 of the drawings, the socket opening is shown noticably larger in diameter than the beam and the annulus defined thereby is shown partially occupied and filled with a forged extension or continuation of the bead. With the above relationship of parts, it will be apparent that tolerances between the beam and its related socket opening or openings is not critical and that the metal made plastics during welding of the parts will, or can be, forged into the interslices or spaces between the parts created by excess tolerances to eliminate such tolerances to a desired limited extent, or completely, if circumstances require.

It is to be understood that in FIG. 8 of the drawings, the connected parts are welded together and are quenched and hardened in the same manner as set forth above in describing the connection between the head H and beam B.

With the novel connecting means that I provide, the connected parts are possitively and permanently mechanically interlocked, one with the other, and the wish to reserve to myself any modifications and/or variations that may appear to those skilled in the art to which this invention pertains.

Having described my invention, I claim:

1. A wrench including an elongate, resilient deflection beam with front and rear ends, a work-engaging head at its front end, a hand grip at its rear end, a dial face-mounted adjacent and in fixed relationship to the rear portion of the beam and, an elongate rigid pointer carried by the head and projecting rearwardly therefrom and into cooperative relationship with the dial face and connecting means connecting the head and the beam in fixed relationship, said means includ ing a rearwardly opening socket opening entering the head and having a substantially flat, rearwardly disposed bottom and a radially inwardly opening annular lock groove adjacent said bottom, said front end of the beam being substantially flat, said beam extending longitudinally through the socket opening with its front end at the bottom of the socket and having an annular lock bead forged adjacent its forward end and projecting radially into the lock groove.

2. A structure as set forth in claim 1 wherein the inner faces defined by the bottom of the socket opening and the front end of the beam are welded.

3. A structure as set forth in claim 1 wherein the inner faces defined by the socket bottom and front end of the beam and by the lock groove and lock bead are welded.

4. A structure as set forth in claim 1 including connecting means connecting the hand grip and the beam in fixed relationship, said means including a forwardly opening socket opening entering the hand grip and having a substantially flat forwardly disposed bottom and a radially inwardly opening annular lock groove adjacent said bottom, said rear end of the beam being substantially flat, said beam extending longitudinally into the socket opening in the hand grip with its rear end at the bottom of said socket and having an annular lock bead forged adjacent its forward end and projecting radially into the lock groove in the socket in the hand grip.

5. A structure as set forth in claim 4 wherein the inner faces defined by the ends of the beam and the bottoms of the sockets are welded.

6. A structure as set forth in claim 4 wherein the inner faces defined by the ends of the beams and the bottoms of the sockets and by the lock grooves and lock beads are welded. 

1. A wrench including an elongate, resilient deflection beam with front and rear ends, a work-engaging head at its front end, a hand grip at its rear end, a dial face mounted adjacent and in fixed relationship to the rear portion of the beam and, an elongate rigid pointer carried by the head and projecting rearwardly therefrom and into cooperative relationship with the dial face and connecting means connecting the head and the beam in fixed relationship, said means including a rearwardly opening socket opening entering the head and having a substantially flat, rearwardly disposed bottom and a radially inwardly opening annular lock groove adjacent said bottom, said front end of the beam being substantially flat, said beam extending longitudinally through the socket opening with its front end at the bottom of the socket and having an annular lock bead forged adjacent its forward end and projecting radially into the lock groove.
 2. A structure as set forth in claim 1 wherein the inner faces defined by the bottom of the socket opening and the front end of the beam are welded.
 3. A structure as set forth in claim 1 wherein the inner faces defined by the socket bottom and front end of the beam and by the lock groove and lock bead are welded.
 4. A structure as set forth in claim 1 including connecting means connecting the hand grip and the beam in fixed relationship, said means including a forwardly opening socket opening entering the hand grip and having a substantially flat forwardly disposed bottom and a radially inwardly opening annular lock groove adjacent said bottom, said rear end of the beam being substantially flat, said beam extending longitudinally into the socket opening in the hand grip with its rear end at the bottom of said socket and having an annular lock bead forged adjacent its forward end and projecting radially into the lock groove in the socket in the hand grip.
 5. A structure as set forth in claim 4 wherein the inner faces defined by the ends of the beam and the bottoms of the sockets are welded.
 6. A structure as set forth in claim 4 wherein the inner faces defined by the ends of the beams and the bottoms of the sockets and by the lock grooves and lock beads are welded. 